Anorectal function following low anterior resection

Rectal function following rectal resection for carcinoma was studied in 43 patients.

Sixteen women and 27 men with a median age of 66 years (range 41-79 years) were included. Twenty-three patients had a diverting ileostomy at the time of resection. Eight patients had a 6-cm colonic J-pouch. Ten patients had anastomotic leakage including two patients without diverting ileostomy. One patient had pre-operative radiation with 25 Gy. The patients were studied at a median 12 months (range 3-30) after rectal resection. Distance from anal verge to the anastomosis was a median 7 cm (range 3-12 cm). Clinical data, anal manometry and rectal compliance were analysed.

Stool frequency was 3 per day (range 1-10). Twenty-two (51%) patients were continent, 11 (26%) were incontinent for flatus, and 10 (23%) were incontinent for faeces (three for liquid and seven for solid stool). Fourteen (33%) patients had constipation, two of whom also had incontinence for solid or liquid stool. The level of the anastomosis for patients with postoperative constipation was 5 cm (range 3-12 cm), while it was 7 cm (range 3-10 cm) for nonconstipated patients (NS). Anal manometry was normal. Rectal compliance was lower in patients with incontinence for liquid or solid faeces than in patients with flatus incontinence only (P < 0.01), and rectal volume tolerability was lower in incontinent patients compared with continent patients (P < 0.05). The rectoanal reflex was present in 31 (72%) patients. There was a negative correlation between maximal rectal volume and stool frequency and between level of the anastomosis and degree of incontinence. Age did not affect functional outcome.

Many patients had a poor functional result following low anterior resection. One in four suffered from incontinence to liquid or solid faeces and one third of the patients experienced constipation. A low level of anastomosis tended to increase stool frequency and carried a higher risk of incontinence. Patients with faecal incontinence tended to have lower rectal compliance and volume tolerability than patients who were continent, while there was no difference in anal pressures.